[Machine] Because the Messenger of Allah ﷺ gave him permission on the day of Khandaq (the Battle of the Trench) when he was fifteen years old, and the Battle of the Trench took place in the month of Shawwal in the fourth year (after the migration to Medina), and there is disagreement regarding his death.
لِأَنَّ رَسُولَ اللهِ ﷺ أَجَازَهُ يَوْمَ الْخَنْدَقِ وَهُوَ ابْنُ خَمْسَ عَشْرَةَ وَالْخَنْدَقُ فِي شَوَّالٍ سَنَةَ أَرْبَعَ وَقَدِ اخْتُلِفَ فِي وَفَاتِهِ